Challenger Bethany Hallam toppled John DeFazio in the race for the Democratic "at-large" seat on Allegheny County Council — the latest case in which an upstart progressive challenger toppled a well-established Democrat.

Generally speaking, races for the 15-member Allegheny County Council don't come with a lot of built-in interest. But Democrats across the county are expected to have a choice between two candidates with notable backgrounds – and the choice to make a generational change.